When different liquids contained in source sub-containers are transferred to target sub-containers, there is a risk of contamination of some liquids with other liquids. One solution that has been used in the past to prevent such contamination consists of filling the target sub-containers manually one at a time, for example by using pipettes or syringes which have been filled in the sub-containers.
However, the disadvantage of this manual filling method is that it is time-consuming, particularly in the presence of a large number of sub-containers. Typically, the filling time for a capillary reservoir (target container) with 1000–5000 canals (target sub-containers) is on the order of 40 to 120 hours. Therefore, it is difficult to imagine industrial application of a manual filling method of this kind.
Manual filling also presents other related disadvantages. Liquid contamination may occur if the operator fills the wrong target sub-container, and then the filling operation must be re-started.
Another disadvantage resulting from manual filling is connected to the particular knack or individual technique developed by each operator in performing the filling operation, and this affects the reproducibility as well as the reliability of the operation. In fact, introduction of the liquid into each target sub-container should be such that there is no formation of inserted air bubbles that might later affect the behavior of the transferred liquid, particularly in the transfer of small volumes of liquids, such as 30 microliters.
Proposals have been made to automate the manual filling of the target sub-containers by using a programmable robot that can fill a pipette or a syringe with an appropriate liquid, bring it to the opening of each sub-container, and transfer the liquid into said sub-container, then repeat these operations for all the sub-containers. Automation of this kind improves the reliability and reproducibility of the transfer, but does not solve the problem of transfer time.
An inherent disadvantage in the filling, including automated filling, of target sub-containers, one after the other, is related to the fact that some liquids that would be transferred have properties that change over time. This is true, for example, in the case of biological products. The concentration may change because of evaporation when the quantities of transferred liquids are very small, for example, less than 10 microliters. When the time required to fill the sub-containers of the target container is substantial, variations may be encountered in the properties between the liquids which have been transferred at the beginning of the filling operation and the liquids which are transferred several hours later. If these liquids are used to perform biological tests, the results of these tests may be biased or even erroneous.
This invention seeks to overcome the disadvantages described above. Certain embodiments provide a device for simultaneous transfer of liquids, particularly different liquids, from a source container to a target container, said transfer being rapid, reproducible, reliable, and capable of automation. Other embodiments of this invention provide a process for simultaneous transfer.